PROJECT SUMMARY The proposed studies will provide critical information to inform immunization policies and practices in the United States. Immunizations are among the most effective health interventions available in the US, with more than 40,000 early deaths and 20 million cases of disease averted within each vaccinated birth cohort. Immunizations are also among the most efficient from an economic perspective. Many older vaccines are cost- saving, while newer vaccines require an investment for health benefits but typically yield cost-effectiveness ratios within a range considered to be cost-effective. As newer vaccines are associated with higher prices and also more likely to avert morbidity than mortality, economic evaluation can provide insights into the value of a new vaccine by weighing trade-offs among the additional investments required, averted disease costs, projected health benefits, and adverse events. The goal of these studies, as part of the Joint Initiative in Vaccine Economics (JIVE), is to address two highly-relevant topics in immunization policy and practice: the economic attractiveness of a hypothetical vaccine for respiratory syncytial virus (RSV) and the costs and potential health benefits of interoperability between provider practices and statewide immunization information systems. Using economic evaluation and decision analysis methods, we will (1) measure the economic burden associated with RSV for patients, caregivers, and family members at both the patient and population level; (2) evaluate projected health and economic outcomes for a hypothetical RSV vaccine, including costs, quality- adjusted life years, and incremental cost-effectiveness ratios, and (3) evaluate practice-level costs and benefits of interoperability between provider practice electronic health records and a statewide immunization information system. Methods will include primary data collection, health utility elicitation, discrete choice experiments, economic evaluation, simulation modeling, dynamic transmission modeling, as well as qualitative analysis.